Abstract: A steel wire having a cross section perpendicular to a longitudinal direction having a flat shape, and an outer shape of the cross section including a pair of linear parts opposing each other, and a pair of curved parts opposing each other and connecting the linear parts. The curved part includes a pair of first regions located at positions near the linear parts, and a second region located at a position between the pair of first regions, a radius of curvature, R1 of the first region is greater than or equal to 0.05 mm but less than 0.15 mm, and a radius of curvature, R2 of the second region is greater than or equal to 0.13 mm but less than or equal to 0.2 mm, and an angle between the linear part and the curved part is greater than or equal to 165 degrees.

Abstract: A plurality of belt layers 7 are superimposed in a radial direction. The belt layers 7 include a plurality of steel cords 10 arranged in parallel in a row and rubber 11. The steel cords 10 have a 1×4 structure in which four filaments 20 are twisted, and when a center-to-center distance between the steel cords 10 in at least two of the belt layers 7 adjacent in the radial direction is T, and an average diameter of virtual circumscribed circles of the steel cords 10 having the 1×4 structure is D, 1.25?T/D?2.25.

Abstract: A steel cord includes one or more core filaments, and outer sheath filaments provided so as to surround the one or more core filaments. The one or more core filaments and the outer sheath filaments have an identical wire diameter and an identical twist pitch. At least one of the one or more core filaments is a waved filament having a bent portion and a non-bent portion along a longitudinal direction.

Abstract: A steel wire having a flat shape in a cross-section perpendicular to a longitudinal direction, wherein an outer shape of the cross-section includes a first straight portion, a second straight portion arranged opposite to the first straight portion, and a first curved portion and a second curved portion that connect the first straight portion to the second straight portion, wherein the first curved portion is arranged opposite to the second curved portion, and wherein a ratio of W1 to W2 is 75% or less, where W1 is an average value of a length of the first straight portion and a length of the second straight portion, and W2 is a maximum distance between the first curved portion and the second curved portion.

Abstract: A plurality of belt layers are laminated in a radial direction. The belt layer includes a plurality of steel cords arranged in parallel and aligned in a row, and rubber. The steel cords have a 1×4 structure in which 4 filaments are stranded. [Tensile rigidity]×[number of ends] is 10,000 N/% or greater and 20,000 N/% or less, and an interface rigidity is 2.5 MPa or higher and 5.0 MPa or lower.

Abstract: A tire includes a steel cord having a plated coating layer, rubber covering the steel cord, the plated coating layer including Cu and Zn, and a bonding layer including Cu2S and CuS provided closer to the rubber than an interface between the steel cord and the rubber, wherein a molar ratio Cu2S/CuS of Cu2S and CuS included in the bonding layer is 1.0 or higher.

Abstract: A steel cord includes a two-layer stranded construction including a core in which two or three core filaments are twisted, and including a one-layer outer sheath in which outer sheath filaments are helically wound around the core and along a longitudinal direction of the core. The core filaments have same filament diameters as the outer sheath filaments, length of lay for the core is same as length of lay for the outer sheath, and length of lay/filament diameter, which indicates a ratio of length of lay to a filament diameter, is between 50 and 75. Two or more filaments selected from among the core filaments and the outer sheath filaments, are crimped filaments each including bent sections and non-bent sections that are repeatedly disposed along the longitudinal direction.

Abstract: Provided is a tire that is lightweight and excellent in riding characteristics while suppressing an increase in cost. A plurality of belt layers 7 are superimposed in a radial direction. The belt layers 7 include a plurality of steel cords 10 arranged in parallel in a row and rubber 11. The steel cords 10 have a 1×4 structure in which four filaments 20 are twisted, and when a center-to-center distance between the steel cords 10 in at least two of the belt layers 7 adjacent in the radial direction is T, and an average diameter of virtual circumscribed circles of the steel cords 10 having the 1×4 structure is D, 1.25?T/D?2.25.

Abstract: Spring steel wire is formed by drawing steel wire including a phosphate film, the weight of the film being in the range of 3.0 to 5.5 g/m2, and R/d being in the range of 1.06×10?3 to 3.92×10?3 where R represents surface roughness; and d represents the diameter of the spring steel wire.